Calculate your pregnancy due date — with trimester info and milestone timeline
— or enter conception date —
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Estimated Due Date (Naegele Rule)
Weeks Pregnant
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Days Until Due
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Trimester
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Conception Date
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Earliest Viable
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40-Week Window
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Milestone
Date
Week
This calculator provides estimates based on standard pregnancy calculations. Always consult your healthcare provider for medical advice and accurate dating via ultrasound.
FREQUENTLY ASKED QUESTIONS
How is due date calculated?
The standard method (Naegele Rule) adds 280 days (40 weeks) to the first day of your last menstrual period, adjusted for cycle length. Ultrasound dating is more accurate, especially for irregular cycles.
What does 40 weeks pregnant mean?
Pregnancy is counted from the first day of your last period, not conception. Conception typically occurs around week 2. So at 40 weeks, the embryo/fetus is about 38 weeks old.
What is the viability threshold?
24 weeks (168 days) is generally considered the threshold of viability — the point at which a premature baby has a meaningful chance of survival with intensive medical care.
What is full term?
Full term is 39-40 weeks. Early term is 37-38 weeks. Late term is 41 weeks. Post-term is 42+ weeks. Babies born before 37 weeks are considered premature.